Method and device for rolling bevel gears



Feb. 26, 1963 F. ERDELYI METHOD AND DEVICE FOR ROLLING BEVEL GEARS Filed Oct. 27, 1958 9 Sheets-Sheet 2 h I I 77W j /Z Z: m M

Feb. 26, 1963 F. ERDELYI 3,078,745

METHOD AND DEVICE FOR ROLLING BEVEL GEARS Filed Oct. 27, 1958 F i 4- 9 Sheets-Sheet s Feb. 26, 1963 F. ERDELYI 3,078,745

METHOD AND DEVICE FOR ROLLING BEVEL GEARS Filed Oct. 27, 1958 9 Sheets-Sheet 4 Fig.5

Feb. 26, 1963 F. ERDELYI 3,078,745

METHOD AND DEVICE FOR ROLLING BEVEL GEARS Filed Oct. 27, 1958 e Sheets-Sheet s Fig. 7

105* i I I M" JNVENTOR Feb. 26, 1963 F. ERDELYI METHOD AND DEVICE FOR ROLLING BEVEL GEARS 9 Sheets-Sheet 8 Filed Oct. 27, 1958 .7N VENTOR I Jam 5% Feb. 26, 1963 ERDELY| 3,078,745

METHOD AND DEVICE FOR ROLLING BEVEL GEARS Filed Oct. 27, 1958 9 Sheets-Sheet 9 TImE Fig.1

.7Nl/ENTOR be manufactured. of,the method to manufacture-direct and sloping toothed bevel gears, bevel gears with circular teeth and .spiral teeth, hypoid bevel gears, palloid bevel gears, as'well as United States Patent '0 METHOD AND DEVICE FOR ROLLING BEVEL GEARS Fereuc 'Erdelyi, 36-75 Normally Road,

Shaker Heights 20, Cleveland, Ohio Filed Oct. 27, 1958, Ser. No. 769,746

Claims-priority, applicationGermany Nov. 2, 195.7 8 Claims. (Cl. 80-16) The invention relates to a method for rolling bevel gears and to a device for carrying out this method.

According to the invention the bevelgear Wheel is clamped and thereafter is heated to the working temperature in the ready clamped condition in the region in which the teeth .are' to be rolled, whereafte'r the teeth are rolled into the blank withoutunclamping in arolling process by means of at leastone bevel 'geartool, the bevel gear being then unclamped .and removed. In. this way it is possible to prepare by rolling a bevel gear in a complete working process, without theinecessity for an after treatment. The precision of the toothing'and the quality of the surface depends essentially on the precision and the surface quality of the bevel gear tool used. For the invention it is of'decisive importance that the bevel gear blank be first clamped and thereafter warmed without delay in the region ofthe material providedfor the tooth ,scaling ofthe surface does not occur, soithat thebev el gear is, in fact ready at the end .of the process and no after treatment is required.

For this it is important in carrying out the method .that the material of the blank-be heated onlyto the. workingtemperature in the region provided .for the toothing.

lnthis way it is secured that the. work piece is unobjectionably clamped atits centralboreand remains centered.

The method allowsthe manufacture of'beyel gears in an extraordinarilyshort time, whereby an essential cheapening of the manufacture of bevel gears is afforded. .Qf especialadvantage is the fact that the carrying out of the method is not restricted tospecial teeth, but allows any kind of teeth to beproducedwith which a bevel ge ar can Itis thus made possible with the help ,eloid bevel gears,.wherein the teeth can be formed also with crowned teeth.

An especial advantage of the method of the invention howeverresides in the properties of the bevel gears produced with its help. Inthe rolling method provided by the inventionthe threads of the working rnateriallare-not broken or destroyed, but the'threads are accommodated to-therolled tooth profile, so that a; substantially increased stability of the rolled bevel gear is afforded.

Preferably the heatingof the region ofithe bevel .gear blank provided for the rolling takes ,place by :elec'tric induction heating, particularly at middle frequencies.

"With the help of this kind of heating it is especially-simple and aboveall very quickly possible to heat the bevel gear blank in the desired place and thedesiredregion to the working temperature. The middle frequency range .of about -l-O, 00O :Hz. is-specially suitable for heatingvso astoreach the necessary heating depth.

In this connecti'or1-as is further explained belowitcan be recommended that. the bevel gear blank be rotated during the blank or the prepared rolled bevelfgear are eifeoted by- 3,078,745 Patented. Feb. 26

. ice

in working obtained. An especially simple-device for carrying outthe method includes a working table rotatably mounted ona, machine upright and rotatable insteps,

on which a'plurality of bevel gear. blanks can be clamped in a circle; moreover in the upright in the axis of the individual clampingidevices of .thework table a clamping gr a loading st ation, heating stations, rolling stations and an unclamping or delivery station are arranged :in;a series corresponding to the desired steps of the process. A deviceisthus provided, which is.-in aposition continueusly vto produce bevel gears from bevel gear blanks, in which the bevel gear blank is introduced at one position of v, lle machine and the prepared rolled bevel gear-is removed at another position. Essentially it is also possible to cons ructgthe device so that a workingtable has somanjy stations that several bevel gears are rolled in a single cycle.

The bevel gear toolsare advantageously driven. in a .form-closed manner about their own axes, whilst the bevel gear blanks :are driven for the pur-PQse of :rolling .onthe bevel gear tools-about their 'axes lying'cent'rally .of theclarnping device. However it is essentially also possible to effect the whole rolling movement by the tool .Ort-he work 'piece, as .is known. in teething machines;

.Thefo'rces which appear during therolling ofthe teeth and which must be taken up by the supports of the work tool and work piece arevery great. For this reason it is .recommendedthat the partofj the upright supporting the roller working tools, which is'described subsequently as the upper part, be connected by a tie rod lying in the axis .of the wworktabletothe part of the upright receiving the work table, which is designatedsubsequently as the lower part. In'this way-it is effected that the mounting: of the tool and the work piece are balancedso that no deforma- ..tion.under the1influence of thehigh rolling pressures takes place. This however is assuming that the bevel. gear fblank is :rolled so thatitrequiresno 'subsequ'ent'treatment.

vAttent'ionis expressly drawn to. the fact that the invention canwbe carried outwith great advantagesiftheiflanks of thebevel gear rolled in'accordance with'the invention are "iiig pressuresitobe taken up. At the remaining-"stations of the work.table,'where the bevel gear blank is: heated-or where it is clamped in the clamping device or uncla'mped and removed "from the clamping device, these mushroom Lheads can-be-of a'smaller'size because here the axial forces are substantially less.

Preferably the support of. the clamping devicesand the clamping and unclarnping'iand ejection of the bevel gear .draulically or pneumatically, withoutelec tric-or mechain ical performance of these subsidiary tasksbeih'g excluded.

Further improvements and advantageous 'featursof the invention are explained 'with reference-to the accompany'ingdrawings' in whichthe' embodiment of the' inve'rition in the form of an example is shown in a simple way in that the drawing is restricted to parts essential to the invention.

In the drawings:

FIGURE 1 is a side view of a machine embodying the invention;

FIGURE 2 is a view of the machine of FIGURE 1 in the direction of the arrows A-B of FIGURE 1;

FIGURE 3 is a section through the work table of the A machine of FIGURES l and 2 along the line IIIIII of FIGURES 1 and FIGURE 4 is a partial view of the right-hand upper section of FIGURE 3 in a larger scale for showing a clamping device in detail;

FIGURE 5 is a horizontal section through the machine along the line VV of FIGURES 1-3 and 6, in which in a part of the figure a section the line VaVa of FIGURE 3 is detailed in chain-dotted line;

FIGURE 6 is a vertical non-linear partial section through the machine, the upper part of FIGURE 6 representing a section along the line VIaVIb-VIc of FIG- URE 5. The lower part of FIGURE 6 represents part of a section along the line VIaVIbVId of FIGURE 5. In addition a section along the line VIaVIbVIc of FIGURE 5 is shown in the lower part of FIGURE 6 in broken lines. The upper part of FIGURE 6 also shows a section along the line VI-VI of FIGURES 2 and 9;

FIGURE 7 is a view of the upper part of FIGURE 6 on a larger scale for showing in detail the drive of the rolling tool (bevel gear rolling wheel);

FIGURE 8 is a view of the middle part of FIGURE 6 on a larger scale for showing in detail the rolling tool operation;

FIGURE 9 is a partial section through the upper part of the machine on the line IX-IX of FIGURES 1 and 6; and

FIGURE 10 is a distance-time diagram for schematically showing the movement of the clamping devices and of the work piece to be rolled therewith, in dependence on time.

The machine has an upright especially of cast steel or of welded construction designated generally by the reference numeral 1. At its lower part 2 a machine table 3 is rotatably mounted on vertical axle 4. At its upper part 5 all tools and in particular the bevel gear rolling wheels are mounted. This upper part 5 is connected to the lower part 2 by means of a tie rod 7 arranged in the axle 4. This tie rod 7 engages with its bolt-like end 8 in a housing 9 provided in the lower part 2 and is secured by a strong wedge 10.. For accommodating the tie rod, the upper part 5 of the upright is provided with a long barrelshaped housing 32, of which the bore 11 receives the tie rod 7. At its upper end the tie rod 7 is provided with a threaded extension 12 on which are screwed the nut and counter-nut 13 which engage on a surface 14 of the upper part5 of the upright.

Within the upright 1, in fact, in its lower part 2, an electric motor is arranged in a manner not shown which drives a V-belt pulley 16 through a multi-belt V-belt drive (see FIGURE 9) which is keyed onto a shaft 17 rotatably mounted in the upper part 5 of the upright. On this shaft 17 a bevel gear 18 is keyed which drives a bevel gear 19 secured to a vertical shaft 20. The motor for driving the bevel gear 16 runs continuously during the operation of the machine.

The lower end of the shaft 20 (see FIGURES 5-6) is provided with a bevel gear 21 which meshes with a bevel gear 22 arranged on a shaft 23 rotatably mounted in the lower part 2 of the upright 1. To the shaft 23 is secured a bevelled pinion 24 which meshes with bevelled teeth 25 (see FIGURE 3) provided on an intermediate wheel 26 (sun wheel). This intermediate wheel 26 (sun wheel) is mounted for free rotation on the tie rod 7 with the help of roller bearings 30. The outer periphery of the ,wheel 26 is provided with frontal teeth 27 which mesh with a plurality of spur wheels 28. The frontal teeth 27 4 extend to such an extent in the direction of the axis of the tie rod 7, that the spur wheels 28 (planet wheels) are movable to a desired extent axially without losing engagement with the frontal teeth 27.

The rotatably mounted work table 3 is provided with a ring of teeth 29 which mesh with a toothed pinion 166 which is not shown and which is driven by an electric motor not shown or by an hydraulically operated piston. In this way the working table 3 can be turned step by step or interruptedly about an axis 4.

On the work table 3 a plurality of clamping devices are arranged uniformly spaced from one another about a circle. These clamping devices are designated 31 in general and are uniformly with one another. At the upper part 5 of the upright machine tools are arranged which will be described later for working on the bevel gear blanks which are secured in the individual clamping devices 3 1. In this way the working table provides a number of different stations, :1 station being formed at which a bevel gear blank is secured to a clamping device and also a further station at which a bevel gear is uncla'mped and removed from a clamping device. In the illustrative example, eight such stations are provided, which are designated A, B, C, D, E, F, G and H (see FIGURE 5). All these stations have like clamping devices 31 arranged on the work table. In the station A the bevel gear blank is introduced into the machine and secured to a clamping device. For this purpose there is provided at the upper part 5 of the upright, namely at the barrel shaped housing 32, in which the bore 11 is provided for receivinng the tie rod 7, a holder 33 which has a magazine 34 in which the bevel gear blanks 35 are arranged one above the other.

After the loading station A there follow for example three heating or prewarrning stations B, C, D. Here the previously clamped bevel gear blank is heated to the working temperature in the zone which is to be toothed. The heating takes place in one or more steps so that for example the working temperature is first reached at the outer surface in the third step D, the temperature at the interior of the zone to be toothed being generally lower, and the bevel gear in the region of its bore 01' its bushing where it is clamped remains substantially be low the working temperature. The work piece 35 clamped in a clamping device at station A is transported by the corresponding rotation of the work table 3 to the station B where by means of an inductor 36 it is heated by induction middle-frequency heating. Thereafter the working table 3 carries the blank through a corresponding rotation to the step C, where with the help of a second inductor 37 it is further heated, whilst at the same time a bevel gear blank which has been introduced at step A and clamped is moved to the first heating station B.

The first-mentioned bevel gear blank is then after its further heating by means of the inductor 37 conveyed through a further rotation of the work table 3 to the station D, where the heating of the region of the first blank to be toothed to the temperature for deformation is completed by means of the inductor 38. The three inductors 36, 37 and 38 are connected to one another by a busbar 39 or by individual transformers in a way not shown. The busbar 39 is secured to the upper part of the upright by means of tongues 49.

In the next following station E takes place a prerolling of the teeth on the bevel wheel blank in a way to be further described below, whereafter the already pre-rolled blank is again heated in the next following station F, this heating being again preferably etfected by middle-frequency induction heating. At the station F connected to the station G the final rolling of the bevel gear blank takes place. The ready rolled bevel gear is then transported from the station G to the station H by means of a further rotation of the work table, where the prepared bevel gear is released and removed.

I working positions.

Thus there accordingly takes place the production of bevel gears by warm rolling continuously in that at each working step of the working table a blank is introduced at the station A and there secured and a completed rolled .bevel gear is removed at the station H.

The working table 3 is provided at its periphery with stop indentations 167 which are arranged for co-operatlon with a stop catch 158 on the machine upright 1 so that at each engagement of the catch in an indentation 167 the number of which corresponds to the number of stations A to H the work table 3 is secured in one of its The stop catch 1.68 can be spring loaded but can however also be controlled hydraulically, for example.

All the working parts connected with the support, clamping and uncla-mping of the bevel gear blanks to be rolled are operated hydraulically. For this purposeas is shown especially in FIGURES 3 and 4-a clamping device housing 41 is provided which has at its lower end a cylindrical space 42 in which an ejector piston 43 and a clamping piston 44 are mounted for axial displacement. The clamping device housing 41 is connected rigidly with the above-mentioned tooth wheel 28, so that the clamping device housing is arranged rotatably in the table 3 about its axis 45 and axially displaceable.

In. the axis 45 of the clamping device a clamping piston rod 4-6 is arranged which is securely connected to the clamping piston 44. In the upper region of the cylindrical space 42 the rod as is surrounded by a bush 47 on which the ejection piston 43 is displaceably arranged by means of correspondingpa-cking 169. This bush 47 connected is at its upper part with .the clamping device housing 41 and at its lower part with an intermediate cover 4-8- through which the rod 46 projects. At its lower side of this intermediate cover 48 engages the outer periphery of the upper end of a bushing 49, which at its upper end projects against a shoulder 50 of the toothed wheel 2-8 connected fast to the clamping device housing 41. In this Way the intermediate cover 48 is held securely in its axial position and separates the lower working space 51 of the ejection piston 43 from the upper working space 52 of'the clamping piston 44; whilst the lower working space of the piston 44 is designated with 53, the upper working space of the ejection piston 43 is provided with the reference numeral 54. The lower working space 55 is not actuated and connected in any way with the interior of the lower part 2.

As is seen especially in FIGURES 3, 4 and 6, the toothed wheel 28- is provided at itslower side with a pressureshoulder 55 which is suitable for supporting the pressure mushroom head 5a. This mushroom head 56 is rotatably mounted with the help of radial bearings 57 and thrust bearings 58 on the plug 59 of a'stepped or difierential piston, which carries the general reference number 60 and comprises the step 61 of smaller diameter and thestep 62 of larger diameter (see FIGURE 6). In thisv way a working space 63 of greater crossesection and an annular working space 64 f smaller cross-section is provided. The cylinder 65 receiving the piston 60 is .connectedsecurely to the :lower part 2 of the upright 1. At the cover 170 of the cylinder 65 an abutment 155 is provided against which the ledge 171 formed between the .two .pistonsteps Hand 62 lies in the upper position of the .piston. 60

InFIGURE. 6 a specially large construction of this supporting head 55 with the stepped piston 60 is shown. This large construction is provided only at the stations 13 and G where .the rolling of the teeth takes place. At the remaining stations correspondingly smaller support rmushroomvheads are arranged as is shown in FIGURES 3 and 4, of which the construction corresponds with that of FIGURE 6.

Through the clarnpingsdevice housingAl projects a projectorrfiozin theformsof a rod, which in the withdrawn position, vvas;is shownin FIGURES 3-and 4 projects at one '6 end into the upper working space 54 of the ejector :piston 43.

The clamping device housing 41' is at its upper endaprovided with a swaged or narrowed down projection '67 which forms a horizontal surface 68 on which a disc 69 lies which is connected securely for example .by means of screws with the clamping device housing 41. The outer diameter of this disc 69 is somewhat greater than the largest diameter of the underlyingiparts of the clamping device housing 41. In the work table in a corresponding way a shoulder surface 7tlis provided on whichlies on ashoulder ring 7 1whichis made from a material of good frictional properties for example bronze.

At the upper surface vof'this shoulder ring-71iis supported the outer part of'the .intermediated'isc 69. Beneath the should-er ring '71 in the clamping device vhousing 41 is provided a ring'shaped working space'7'2 which is'sealed at the shoulder ring '71 by a packing ring 73'.

The ejecting lrodl65 projects through the disc-69 and;engages with its upper end against the adjustablework piece support 74- which is connected by a .spring. and groove connection '75 for axial displacement with respect to theclamping device 3'land for rotation therewith for efiectingthe ejection. For exact.tran sfer of turning force from the 'clamping deviee Slate the work piece 35 moreover a further spring and groove assembly 76 is arranged between the piston rod 45 and the projection 67 of the clamping device 31.

Atthe upper end of the piston rod a conical body 78 is rcleasably connected by means of a screw 77 connected thereto. This conical ,body acts'in a known wayjwith its conical surface on the upper conicalsurface 79 of a split spring chuck or collet 80 of which the lower conicalsurface .81 liesagainst aconical surface-82 which is provided at the outer .end of the abutment67 of the clamping device housing 41. The split collet .Sllis cylindrical at its ,outerperiphery and is pushed into the bining of a bevel wheelfblank 35Yfor the purpose of securing this. Ifnow the conical body 78 is further secured to the piston. rod .46 andthe-piston rod is moved downward, the spring collet 80 is pressedoutwardly whereby the bevel gear blank 351s securely fastened land'clamped ,to the upper surface 84 of the closure disc 74 (tool .support 74).

In the closure disc 74 (-tool surface support 74-) a series of uniform. b'orings 83 divided'by a diameter are provided, th'rough'which in forming a shoulder '85 a threaded bolt 86 projects, which is screwedinto the intermediate disc 69.. A coilspring 87is arranged between the head of thebolt 86 and the shoulder 85. i i

The working table 3 is rotatably mounted by means of'a hub 83 on'the'tie rod 7, in that itis supported uniformly over the pressure and roller support 39 of. the intermediate wheel 26 (suirwheel) and therewith the housing-90f the'lower part 2 of the'upright.

.Before going intothe method ofworking of-the clamping'device 3d, the rollertools and their drive will beexplained. Over the shaft 17 which is rotatablyjmounted inthe upper part '5 of the machine upright (s'eefFIG- URES 6, 7' and 9) andwhichis driven by the common driving roller motor, a shaft9t) is mounted parallel toit.

This shaft 9ti is dri'ven from the Shilfffl] through agear changing device 9 1 of which the input wheel is d ejsi'gnated by 9-2 .and'the output wheel by 93. The gear change vcan be adjusted in known way to alter the'speed reduction ratios. To this purpose a closable door 94- pro vided in the upper part 50f the'upright.

'IFIQDI lhB shaft 9.0twoshafts 95 extending'parallel' to one another are driven in a complete1y;similar.way. The axis of the one shaft 95 is desi-gnatedby fifi. and thatof -tl1e other shaft95- by 97. Theshaft 9.5 withthe axis ment in'that each of thetool attachments is mounted 'in a hub-like housing 102, 103 which forms a part of the top of the upright. As can be seen from FIGURE 2, two housings 102, 103 of this kind and therefore two roller tool attachments are provided, which correspond to stations E and G. It is however clearly to be understood that a single roller tool station or more than two roller tool stations can be provided. As will be subsequently given separately there relates to each rolling tool station E, G, three bevel gear rolling tools 6. It is however also possible at each station to increase or reduce the number of such tools.

In the following only one gear cover of a shaft is spoken of and it is emphasized that the gear covers of both drive shafts 95 and the associated roller tools are constructed in completely similar ways.

The shaft 95 drives a bevel gear pinion 104 which meshes with a pinion 105 (bevel gear), the bevel gear pinions 104, 105 being arranged in a special housing 106 above the bushing 103 or 162, which is securely connected to the bushing 103, 102 and thus with the upper part of the machine upright. The bevel gear 105 is securely connected to a toothed member (hollow shaft) 107, through the centre of which a shaft 108 extends. The toothed body 107 (hollow shaft) is rotatably mounted on the housing 106 or the cover 109 associated there with. The shaft 108 is turnably mounted in a drumshaped support housing or body 110, by means of two support bodies (roller supports) 111, 112, in that axial displacement between the shaft 108 and the support body 110 is prevented by means of shoulders 113, 114 (nut with counter nut). The support body 110 is secured against rotation but is however axially displaceable in a bore 115 of the housing 103 of the machine upright 1. At the upper part of the outer periphery of the support body 110 is cut a square section trapezoidal or buttress type thread 116 on which is threaded a nut 117 which is made from material with good frictional properties, for example bronze, and which is provided on its outer periphery with worm teeth 118. In this worm thread 118 engages a worm gear 119 which is mounted for rotation in the housing 103 or 162 and can be turned manually by means of a hand wheel 120 which is secured on the shaft of the worm gear 119. By turning the hand wheel the axial position as regards height of the support body 110 and therewith of the shaft 108 can be precisely adjusted to a fraction of a millimeter. Instead of the hand wheel 120 a positioning motor can of course be provided for adjusting the axial height of the shaft 108.

In this connection the upper part of the shaft 108 is provided with a spline 121 which engages in a correspondingly long constructed spline 122 in the bore of the bevel wheel body 107. In this way the axial position of the shaft can be altered without influencing the working engagement between the body 107 and the shaft 108.

At the lower end of shaft 108 is secured a bevel gear 123 which meshes with a bevel gear 124. The two bevel gears are connected below two cover housings 125, 126 which are secured to the support body 110. The bevel gear 124 is connected by a spring and groove connection 127 for rotation with a tool reception head 128 which is rotatably mounted by means of radial roller supports 129, 130 and axial roller supports 131, 132 in a cover support body 125, 126, which unifies the assemblies. This tool reception body 128 has a central bore through which a threaded bolt 133 projects. The threaded end 134 of this bolt engages in a corresponding threaded bore which is provided at the far end of the tool attachment 6. This tool attachment is at its outer end provided with bevel teeth 135 and moreover has a bevel seating surface 136, which is able to co-operate with a corresponding seating surface of the tool reception 128. At the conical seating surface 136 is attached a cylindrical projection 137 in which the threaded boring for receiving the threaded end 134 of the bolt 133 is provided. At the threaded bore is connected a bore 172 which reaches to engage at the teeth 135 of tool attachment 6.

In that the bolt 133 can be screwed up from outside, the bevel gear tool 6 with its seating 136 and its cylindrical projection 137 can be inserted within the tool reception head 133 and secured thereto.

The threaded bolt 133 has a central bore 138 which stands in connection with a water connection 139 through a transverse boring and is sealed to the base of the bore 172 by means of an extension tube 140 and therewith continued to be sealed under the teeth 135 of the tool 6. The tube 140 dips with a great deal of play or intermediate space into the bore 172 of the tool attachment 6. A cylindrical space 141 is left free around the bolt 133 and is in connection with a water connection 145 through a transverse bore and is also connected with the bore 172 of the tool inset 6 through longitudinal bores, not shown, which are provided in the tool inset 6 outside its axis. Cooling water enters for example at the connection 145 fiows through the annular space 141 to the bore 172 within the tool 6, there cooling the tool, and travels then in a more or less warmed condition through the tube 140 and the boring 138 to the connection 139 and out. The cooling medium can then be recycled and it is possible to use another cooling liquid instead of water.

As is clear especially from FIGURES l and 2, but also from FIGURES 6 and 8, each shaft 108 drives by means of the bevel gear 123 for example three of this kind of bevel gear roll working tool 6 which are arranged uniformly about its periphery. The number of rolling tools at each station is howeveras already emphasized abovedependent in particular on the shape and size of the work piece.

The clamping device 31 and the working spaces 63, 64 of the mushroom support head 56, are hydraulically actuated and controlled. The lower working space 53 of the clamping piston remains unactuated whilst the upper working space 52 of the clamping piston is actuatcd for the purpose of clamping a bevel gear blank 35, by pressure fluid which flows in through ducts 146 provided in the working table 3 and a long annular space 147 (grooved canal) in the clamping device housing 41. In the corresponding way the lower ejector working space is actuated by pressure fluid through a long annular space 148 (grooved canal) and ducts 149. The upper working space 54 of the ejector piston is actuated by pressure fluid through grooved ducts 150 and conduits 151. The return space 72, which is provided in the clamping device housing 41 is actuated by pressure means through duct 152, whilst through a channel 153, leaking oil is led from the outer peripheries of the discs 69 and 74; in this connection packing collars 154 are provided for sealing this outer periphery. The inand out-flow of the oils takes place in a manner not shown by bores 174 which are provided in the tie rod 7 (see FIGURE 5).

The working table is cooled by means of water from within. To this purpose the individual clamping devices are located in a barrel-like housing 156 which forms a part of the working table 3 (see in this connection the chain dotted line of FIGURE 5). This barrel-like housing is connected with the interior boss 157 of the working table by links 158 in which the oil ducts 147, 149, 151, 152 and 153 are arranged. In these links, moreover, are provided windows 159, so that the single chambers 160 formed in this way are in connection with one another. Each of these chambers 160 has an inlet and outlet duct in that for example a bore 161 serves as the outlet duct for cooling water and the bore 162 is provided for the inlet. A cap 142 transfers the force of the two nuts 163 to the table 3 and provides two annular spaces 164, 165 which are sealed by packing rings 143, 144 and from which the inflow and outflow of the water for cooling the working table takes place through the bores 161, 162.

The clamping devices 31 are adjusted by means of a master wheel, a stencil or template, or by normal means.

In this'way the support head 56 is moved against the abutment 155 in FIGURE 6. This abutment 155 secures all the clamping devices in the highest position whereby each clamping device provided at the roller stations E and G reaches the highest position first at the end of the rolling or forming process.

In the distance-time diagram of FIGURE the distance covered by the clamping devices 31 and therefore by the workpieces to be rolled are set out in dependence on time (the distance as ordinate and the time as abscissa). The solid line drawn shows the circumstances at heating at one of the stations A, B, C, D, and F, the chain dotted line those in rolling or forming at the stations E and G.

On heating, according to the displacement-time diagram of FIGURE 10, the mushroom support head is quickly moved into its upper position against the abutment 155 (trend line c) and remain during the whole heating process in their upper position (trend line d). Whilst the support head for the heating station is acted upon by means of a low pressure pump only, the same low pressure pump and in addition a high pressure pump of lower delivery serve for operating the support heads for the two rolling stations. Both pumps operate also the working space 63 of FIGURE 6. If however the clamping device 31 in a rolling station E, G accelerates according to trend line e of FIGURE 10 and the roller tool comes into engagement at the corner point P of the trend line, then is according the displacement-time diagram of FIGURE 10, the support shoulder 56 is not in its upper position. The resistance increases so that the low pressure pump is no longer in the position to overcome the operating resistance and at this time only the high pressure pump is supplying with a corresponding retardation of the lifting of the lever 56 and therewith of the clamping device 31 and the Work piece during the rolling (see trend line g). The delivery quantity of the high pressure pump is proportioned to the working velocity of the rollers. In both the Working stations E and G the support head again reaches the abutment 115 at the end of the rolling process in that during the rolling process the profile is only roughly rolled out, whilst the completion rolling produces the final profile. The pressure of the pump however then increases in order quickly to reduce after reaching the highest pressure of an adjustable over-pressure valve or in dependence on the possible adjustment of a time meter (trend line 11), whereafter the annealed work piece is quickly moved away from the working tool, in order to prevent excessive heat transfer to the tool.

All the clamping devices of the working table are positioned at this height. After a bevel gear blank 35 is clamped in the station A by actuation of the working space 52, this working space remains under pressure during'the whole cycle, so that the bevel gear blank remains clamped. Shortly before the further movement of the Working table 3 through one division however the working space 63 of the support pillar 56 is discharged and the annular return space 64 is charged. About the same time pressure fiuid enters into thereturn space 72 of the housing 41 of the clamping device. Then the support head 56 moves back into its lower position. At the same time the whole housing of the clamping device, which consists of parts 41, 69 and 74, is moved back into the position shown in FIGURE 3, in which the disc 71 mounted resting in the work table 3 serves as an abutment. The rotation of the whole clamping device about the axis 46 is thus permanently carried on, so that the undersurface of the disc 69 is slidingly supported on the upper surface of the disc 71. In this return position a sufiicient clearance of for example five millimeters between the lower surface of the support head 56 must be allowed to remain. At this time the table 3 can be returned to a further position, whereon the return working space 72 and the working'space 64 are discharged whilst the work- 10 ing space 63 loads the support head, whereon the whole clamping device 31 with the bevel wheel blank '35'clamped thereon is raised to the desired position, whereafter this blank is heated by means of inductor 36 in the first step and is turned'about its own axis 45.

This cycle'is continued in the stations C, D, BF and G, the blank not being heated in stations E and 6, but by means of the toothed tool wheel 6 is provided by a rollingprocess with teeth by rolling. If then after the ending of the preliminary rolling at the station G the ready rolled bevel wheel is transported to the station H, then moreover in the described way the support shoulder 56 is disengaged and thewhole housing 41, 69, 74 is returned by actuation of the return working space 72. However now the Work space 52 is also discharged so that the collet is -nolonger under pressure. At this time the lower rejector space 51 is actuated by the pressure fluid, so that the rejection piston 43 moves upwards and pushes upward the rejection rod 66. The rejector rod 66 at this time lifts the closure disc 74 (work piece support 74) against the resistance of the spring 87, on which rests the -Wheel blank 35 now provided with teeth. In this way the gear wheel is lifted out of the region of the collect =80 and can 'be ejected at the station H in a known and not shown way, for example with a single stripper. The work space 51 is now discharged and the work space 54' is actuated "by the pressure means, so that the rejeotor piston 43 is chine having a base, a .Wbfk table rotatably mountedon said base, means intermittingly rotatably indexing said work table, a plurality of rotatable bevel gear blank clamping means mounted on-said work table atequal distances from the axis'thereof, gear blank loading means comprising a loading station mounted onsaid base above said work table adapted to place a gear blank in said clamping means as the clamping means are positioned thereunder, at'least one heating means comprising'aheating station mounted on said base above said work table adapted to heatthe clamped gear'blank after leaving the loading station, at least one bevel gear rolling tool mounted .on said :base above said work table comprising arolling station forming gear teeth on the blank after -the.clamped blank leaves the. heating station, and means unclarnping and removing the formed gear from the clamping meanscornprising an unloading station monuted on said'base after gear leaves the rolling station.

2. Apparatus for rolling bevel-gears as in claim 1,

wherein-a plurality of heating stations are mounted on said base successively "heating the gear blank prior to indexing the work table to move the' blank-to the rolling station.

3. Apparatus for rolling bevel gears as in -claim 1, wherein a plurality of rolling stations are mounted on said'base, .wherein the rolling of the blank is accomplished in stages and a heating station interposed between the adjacent rolling stations, to reheat the blankbetween rolling stages.

4. Apparatus for rolling bevel gears, comprising a machine havin'ga base, a work table rotatably mounted .on said base, means intermittingly rotatably indexing said work'table, a pluralityof rotatable bevel gear blank clamping, means mounted on said work table at. equal distances from the axis thereof, means rotating said clamping means with respect to said work table, means supporting said clamping means'within said work table for axial movement thereto, gear blank loading means comprising a loading station mounted on said base above said work table adapted to place a gear blank in said clamping means as the clamping means are positioned thereunder, at least one heating means comprising a heating station mounted on said base above said Work table adapted to heat the clamped gear blank after leaving the loading station, at least one bevel gear rolling tool mounted on said base above said Work table comprising a rolling station forming gear teeth on the blank after the clamped blank leaves the heating station, means unclamping and removing the formed gear from the clamping means comprising an unloading station mounted on said base after the gear leaves the rolling station, and means mounted on said base below said work table and in alignment with said loading, heating, rolling and unloading stations engaging and axially moving said clamping means and gear blank toward and away from said stations after each indexing of said work table.

5. Apparatus for rolling bevel gears comprising a machine having a base, a work table rotatably mounted on said base, means intermittingly rotatably indexing said work table, a plurality of rotatable bevel gear blank clamping means mounted on said work table at equal distances from the axis thereof, gear blank loading means comprising a loading station mounted on said base above said work take adapted to place a gear blank in said clamping means as the clamping means are positioned thereunder, at least one heating means comprising a heating station mounted on said base above said work table adapted to heat the clamped gear blank after leaving the loading station, at least one bevel gear rolling tool mounted on said base above said work table comprising a rolling station forming gear teeth on the blank after the clamped blank leaves the heating station, said rolling station including a tubular support body mounted for axial movement on saidlbase coaxial with the axis of the clamping means and gear blank located at the rolling station, a drive shaft concentrically rotatably supported within said tubular body, said rolling tool rotatably mounted on said body having an axis obliquely disposed to the axis thereof, gear means establishing a driving connection between said drive shaft and said rolling tool, and means mounted on said base selectively axially positioning said support body thereto.

6. The method of producing bevel gear wheels by hot rolling, comprising the sequential steps of clamping a cold bevel gear blank in a holder and rotating the holder and gear blank, induction heating the clamped rotating bevel gear blank in several predetermined graduated temperature stages allowing a predetermined time to elapse between each of said heating stages to allow the heat to be conducted inwardly of the material thus evenly heating said bevel gear blank to a predetermined temperature and depth in the localized area in which the teeth are to be formed, prerolling the teeth of the clamped rotating bevel gear blank by means of at least one preminary bevel gear tool, intermediate induction heating the prerolled teeth in the localized area thereof to compensate the loss of heat during prerolling, finish-rolling the teeth of the clamped rotating blank by means of at least one finish bevel gear tool and unclarnping and removing said finished bevel gear wheel from the holder.

7. A machine for rolling bevel gears comprising a machine base, a work table rotatably mounted on said base, means intermittingly rotatably indexing said work table, a plurality of rotatable bevel gear blank clamping means mounted on said work table at equal distances from the axis thereof, gear blank loading means mounted on said base above said work table forming a loading station adapted to place a gear blank in said clamping means as the clamping means are positioned thereunder, induction heating means comprising a plurality of heating stations mounted on said base above said work table, said heating means being adapted to heat the clamped rotating gear blank indexed from the loading station through said heating stations in the localized zone of the teeth to be rolled in a graduated predetermined manner with an even temperature to a predetermined depth, at least one bevel gear prerolling tool mounted on said base above said work table forming a prerolling station for rolling preliminary teeth on the rotating blank after the clamped blank is indexed from the last heating station under said prerolling station, induction heating means comprising an intermediate heating station mounted on said base above said work table, said heating means serving to compensate for the loss of heat of said blank after the clamped blank is indexed from the prerolling station, at least one bevel gear finish rolling tool having a finished cross-sectional form of the desired teeth and being mounted on said base above said work table forming a finish-rolling station for said prerolled blank after the clamped rotating blank is indexed from said intermediate heating station and said finish-rolling station, and means unclamping and removing the finished bevel gear from the clamping means comprising an unloading station mounted on said base after the bevel gear leaves the finish-rolling station.

8. A machine for rolling bevel gears, comprising a machine base, a work table rotatably mounted on said base, means intermittingly rotatably indexing said work table, a plurality of rotatable bevel gear blank clamping means mounted on said work table at equal distances from the axis thereof, means rotating said clamping means with respect to said work table, means supporting said clamping means within said work table for axial movement thereto, gear blank loading means mounted on said base above said work table forming a loading station adapted to place a gear blank in said clamping means as the clamping means are positioned thereunder, induction heating means comprising a plurality of heating stations mounted on said base above said work table, said heating means being adapted to heat the clamped rotating gear blank indexed from the loading station through said heating stations in the localized zone of the teeth to be rolled in a graduated predetermined manner with an even temperature to a predetermined depth, at least one bevel gear prerolling tool mounted on said base above said work table forming a prerolling station for rolling preliminary teeth on the rotating blank after the clamped blank is indexed from the last heating station under said prerolling station, induction heating means comprising an intermediate heating station mounted on said base above said work table, said heating means serving to compensate the loss of heat of said blank after the clamped blank is indexed from the prerolling station, at least one bevel gear finish rolling tool having a finished cross-sectional form of the desired teeth and being mounted on said base above said work table forming a finishing rolling station for said prerolled blank after the clamped rotating blank is indexed from said intermediate heating station to said finish-rolling station, and means unclamping and removing the finished bevel gear from the clamping means com prising an unloading station mounted on said base after the bevel gear leaves the finish-rolling station and means mounted on said base below said work table and in alignment with said loading, heating, rolling and unloading stations engaging and axially moving said clamping means and gear blank toward and away from said stations after each indexing of said work table.

References Cited in the file of this patent UNITED STATES PATENTS 1,240,917 Anderson Sept. 25, 1917 1,240,918 Anderson Sept. 25, 1917 1,241,482 Weaver Sept. 25, 1917 1,669,818 Gleason et a1. May 15, 1928 1,835,591 Bollard Dec. 8, 1931 1,952,491 Bush et al Mar. 27, 1934 2,091,578 Batie Aug. 31, 1937 2,182,799 Parr Dec. 12, 1939 (Other references on following page) 13 UNITED STATES PATENTS Strickland May 14, 1946 Finzel July 15, 1947 Stiven Mar. 15, 1949 Johnson July 26, 1949 14 Harrison Sept. 11, 1951 Weingart June 16, 1952 FOREIGN PATENTS Great Britain Apr. 23, 190-6 Great Britain Apr. 17, 1957 

4. APPARATUS FOR ROLLING BEVEL GEARS, COMPRISING A MACHINE HAVING A BASE, A WORK TABLE ROTATABLY MOUNTED SAID WORK TABLE, A PLURALITY OF ROTATABLE BEVEL GEAR BLANK CLAMPING MEANS MOUNTED ON SAID WORK TABLE AT EQUAL DISTANCES FROM THE AXIS THEREOF, MEANS ROTATING SAID CLAMPING MEANS WITH RESPECT TO SAID WORK TABLE, MEANS SUPPORTING SAID CLAMPING MEANS WITHIN SAID WORK TABLE FOR AXIAL MOVEMENT THERETO, GEAR BLANK LOADING MEANS COMPRISING A LOADING STATION MOUNTED ON SAID BASE ABOVE SAID WORK TABLE ADAPTED TO PLACE A GEAR BLANK IN SAID CLAMPING MEANS AS THE CLAMPING MEANS ARE POSITIONED THEREUNDER, AT LEAST ONE HEATING MEANS COMPRISING A HEATING STATION MOUNTED ON SAID BASE ABOVE SAID WORK TABLE ADAPTED TO HEAT THE CLAMPED GEAR BLANK AFTER LEAVING THE LOADING STATION, AT LEAST ONE BEVEL GEAR ROLLING TOOL MOUNTED ON SAID BASE ABOVE SAID WORK TABLE COMPRISING A ROLLING STATION FORMING GEAR TEETH ON THE BLANK AFTER THE CLAMPED BLANK LEAVES THE HEATING STATION, MEANS UNCLAMPING AND REMOVING THE FORMED GEAR FROM THE CLAMPING MEANS COMPRISING AN UNLOADING STATION MOUNTED ON SAID BASE AFTER THE GEAR LEAVES THE ROLLING STATION, AND MEANS MOUNTED ON SAID BASE BELOW SAID WORK TABLE AND IN ALIGNMENT WITH SAID LOADING, HEATING, ROLLING AND UNLOADING STATIONS ENGAGING AND AXIALLY MOVING SAID CLAMPING MEANS AND GEAR BLANK TOWARD AND AWAY FROM SAID STATIONS AFTER EACH INDEXING OF SAID WORK TABLE. 